Historical Field Records Reveal Habitat as an Ecological Correlate of Locomotor Phenotypic Diversity in the Radiation of Neotropical Geophagini Fishes.

AbstractPhenotypic macroevolutionary studies provide insight into how ecological processes shape biodiversity. However, the complexity of phenotype-ecology relationships underscores the importance of also validating phenotype-based ecological inference with direct evidence of resource use. Unfortunately, macroevolutionary-scale ecological studies are often hindered by the challenges of acquiring taxonomically and spatially representative ecological data for large and widely distributed clades. The South American cichlid fish tribe Geophagini represents a continentally distributed radiation whose early locomotor morphological divergence suggests habitat as one ecological correlate of diversification, but an association between locomotor traits and habitat preference has not been corroborated. Field notes accumulated over decades of collecting across South America provide firsthand environmental records that can be mined for habitat data in support of macroevolutionary ecological research. In this study, we applied a newly developed method to transform descriptive field note information into quantitative habitat data and used it to assess habitat preference and its relationship to locomotor morphology in Geophagini. Field note-derived data shed light on geophagine habitat use patterns and reinforced habitat as an ecological correlate of locomotor morphological diversity. Our work emphasizes the rich data potential of museum collections, including often-overlooked material such as field notes, for evolutionary and ecological research.

Endoparasitic helminth fauna and diet of Geophagus sveni (Pisces) in Upper Paraná River basin.

In freshwater ecosystems, parasite infection patterns are influenced by factors including spatial-temporal variations, host diet, and habitat. Fish often change diets, affecting their parasite communities. This study focused on non-native host fish Geophagus sveni, aiming to characterize diet and endoparasitic helminth fauna patterns in the invaded area, investigating spatial and seasonal possible differences of endoparasite infections and correlating with host diet, in São José dos Dourados River and Tietê River areas. The host fish were collected in these areas during the dry and rainy season using gillnets. The endoparasites were collected and preserved in alcohol and identified using taxonomic methods, and stomach contents were examined for diet analysis. Parasitism descriptors were calculated and evaluated spatially and seasonally by ANOVA and the Kruskal-Wallis tests. PERMANOVA assessed G. sveni diet differences, and RDA correlated the endohelminth abundance with the host diet. Two endoparasites were recorded: metacercariae of Austrodiplostomum compactum (Trematoda) and larvae and adults of Raphidascaris (Sprentascaris) lanfrediae (Nematoda). Spatial differences were observed for the mean abundance and prevalence of R. (S.) lanfrediae and A. compactum prevalence. Seasonal variations of parasitic descriptors occurred for the nematode in the Tietê River area. The detritus and aquatic insects were the most consumed items by G. sveni. Detritus consumption positively correlates with nematode abundance. The findings indicate that factors such as artificial channels and rainfall, which can influence resource availability, may affect the fish's diet and potentially influence the structure of its endoparasite community. The study emphasizes the importance of understanding trophic chain-transmitted parasites and calls for further research in Neotropical environments.

Biogeography of Greater Antillean freshwater fishes, with a review of competing hypotheses.

In biogeography, vicariance and long-distance dispersal are often characterised as competing scenarios. However, they are related concepts, both relying on collective geological, ecological, and phylogenetic evidence. This is illustrated by freshwater fishes, which may immigrate to islands either when freshwater connections are temporarily present and later severed (vicariance), or by unusual means when ocean gaps are crossed (long-distance dispersal). Marine barriers have a strong filtering effect on freshwater fishes, limiting immigrants to those most capable of oceanic dispersal. The roles of vicariance and dispersal are debated for freshwater fishes of the Greater Antilles. We review three active hypotheses [Cretaceous vicariance, Greater Antilles-Aves Ridge (GAARlandia), long-distance dispersal] and propose long-distance dispersal to be an appropriate model due to limited support for freshwater fish use of landspans. Greater Antillean freshwater fishes have six potential source bioregions (defined from faunal similarity): Northern Gulf of México, Western Gulf of México, Maya Terrane, Chortís Block, Eastern Panamá, and Northern South America. Faunas of the Greater Antilles are composed of taxa immigrating from many of these bioregions, but there is strong compositional disharmony between island and mainland fish faunas (>90% of Antillean species are cyprinodontiforms, compared to <10% in Northern Gulf of México and Northern South America, and ≤50% elsewhere), consistent with a hypothesis of long-distance dispersal. Ancestral-area reconstruction analysis indicates there were 16 or 17 immigration events over the last 51 million years, 14 or 15 of these by cyprinodontiforms. Published divergence estimates and evidence available for each immigration event suggests they occurred at different times and by different pathways, possibly with rafts of vegetation discharged from rivers or washed to sea during storms. If so, ocean currents likely provide critical pathways for immigration when flowing from one landmass to another. On the other hand, currents create dispersal barriers when flowing perpendicularly between landmasses. In addition to high salinity tolerance, cyprinodontiforms collectively display a variety of adaptations that could enhance their ability to live with rafts (small body size, viviparity, low metabolism, amphibiousness, diapause, self-fertilisation). These adaptations likely also helped immigrants establish island populations after arrival and to persist long term thereafter. Cichlids may have used a pseudo bridge (Nicaragua Rise) to reach the Greater Antilles. Gars (Lepisosteidae) may have crossed the Straits of Florida to Cuba, a relatively short crossing that is not a barrier to gene flow for several cyprinodontiform immigrants. Indeed, widespread distributions of Quaternary migrants (Cyprinodon, Gambusia, Kryptolebias), within the Greater Antilles and among neighbouring bioregions, imply that long-distance dispersal is not necessarily inhibitory for well-adapted species, even though it appears to be virtually impossible for all other freshwater fishes.

Ecomorphology and Morphological Disparity of Caquetaia Kraussii (Perciformes: Cichlidae) in Colombia.

Understanding the interspecific morphological variability of Caquetaia kraussii (Perciformes: Cichlidae) between different localities in its distribution range is becoming essential, as this species constitutes a valuable resource for the economy and subsistence of the local human communities where it is endemic in Colombia and Venezuela. In order to develop efficient farming and handling plans for this species, a deep understanding of the factors and mechanisms generating morphological variability is crucial. This study analyzes the morphological variability of C. kraussii by using geometric morphometrics in four localities distributed between the Dique and North channels, which are part of the Bolívar department in Colombia. Likewise, the effect of environmental variables such as temperature (T°), dissolved oxygen (OD) and pH on morphological variability was analyzed using a partial least squares approach. The results show that environmental stress has an influence on ~10% of the body shape of C. kraussii, whereas ~90% of the body shape is not directly influenced by environmental parameters, suggesting an effect from stress related to sexual dimorphism. Similarly, the analyses show shape variation among localities, mainly between populations of lotic environments and those of lentic environments. This morphological disparity seems to be subject to environmental and sexual stresses in the different localities.

A new species of Geophagus (Teleostei: Cichlidae): Naming a cichlid species widely known in the aquarium hobby as 'Geophagus sp. Tapajos red head'.

A new species of Geophagus sensu stricto is described from the Tapajos River basin, Brazil, elevating the number of species of the genus to 21. The new species is of commercial importance and is known in the aquarist trade as Geophagus 'red head'. The new species is diagnosed using an integrative approach, based on mitochondrial DNA analysis along with morphological evidence. The new species is distinguished from all congeners by the absence of markings on the head, the bar pattern composed by nine vertical bars on the flanks and the presence of distinct longitudinal bands in the caudal fin. Additionally, it shows a genetic distance of at least 2.0% in cytochrome b gene sequences from its closest congeners. Molecular analysis including most genera of Cichlidae from South America corroborates that the new species belongs to the group of Geophagus sensu stricto.

Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus / Estudos anatômicos comparativos dos nervos cranianos de embriões totalmente formados da tilápia do Nilo Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus

The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.

A organização das raízes, gânglios e a distribuição periférica dos nervos cranianos dos embriões totalmente formados de Oreochromis niloticus são examinados nas seções transversais seriais. Esses nervos carregam fibras, que também foram analisadas. Os resultados deste estudo demonstraram que o nervo glossofaríngeo se origina por meio de apenas uma raiz, que sai do crânio pelo forame glossofaríngeo. Este nervo fornece fibras (visceromotoras) para os primeiros músculos levantadores do arco branquial interno e externo. Existe um único gânglio epibranquial (petroso) localizado extracranialmente. Nervus glossopharyngeus tem três ramos; faríngeo, pretramticus e póstrematicus. O ramo faríngeo contém apenas fibras viscerossensoriais ­ gerais para o epitélio faríngeo e especiais para o pseudobrânquio. Fibras viscerossensoriais gerais também são transportadas por ramos pretrematicus e posttrematicus para o revestimento epitelial da faringe. As fibras sensoriais especiais são transportadas pelo ramus pretrematicus para as papilas gustativas e pelo ramus posttrematicus para os filamentos branquiais. O ramo pretrematicus também carrega fibras visceromotoras para o primeiro adutor arcus branchialis e para o primeiro músculo oblíquo ventral.

Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus / Estudos anatômicos comparativos dos nervos cranianos de embriões totalmente formados da tilápia do Nilo Oreochromis niloticus (Ostiechthyes Cichlidae). I. Nervus glossopharyngeus

The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.

A organização das raízes, gânglios e a distribuição periférica dos nervos cranianos dos embriões totalmente formados de Oreochromis niloticus são examinados nas seções transversais seriais. Esses nervos carregam fibras, que também foram analisadas. Os resultados deste estudo demonstraram que o nervo glossofaríngeo se origina por meio de apenas uma raiz, que sai do crânio pelo forame glossofaríngeo. Este nervo fornece fibras (visceromotoras) para os primeiros músculos levantadores do arco branquial interno e externo. Existe um único gânglio epibranquial (petroso) localizado extracranialmente. Nervus glossopharyngeus tem três ramos; faríngeo, pretramticus e póstrematicus. O ramo faríngeo contém apenas fibras viscerossensoriais — gerais para o epitélio faríngeo e especiais para o pseudobrânquio. Fibras viscerossensoriais gerais também são transportadas por ramos pretrematicus e posttrematicus para o revestimento epitelial da faringe. As fibras sensoriais especiais são transportadas pelo ramus pretrematicus para as papilas gustativas e pelo ramus posttrematicus para os filamentos branquiais. O ramo pretrematicus também carrega fibras visceromotoras para o primeiro adutor arcus branchialis e para o primeiro músculo oblíquo ventral.

Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus

Abstract The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.

Resumo A organização das raízes, gânglios e a distribuição periférica dos nervos cranianos dos embriões totalmente formados de Oreochromis niloticus são examinados nas seções transversais seriais. Esses nervos carregam fibras, que também foram analisadas. Os resultados deste estudo demonstraram que o nervo glossofaríngeo se origina por meio de apenas uma raiz, que sai do crânio pelo forame glossofaríngeo. Este nervo fornece fibras (visceromotoras) para os primeiros músculos levantadores do arco branquial interno e externo. Existe um único gânglio epibranquial (petroso) localizado extracranialmente. Nervus glossopharyngeus tem três ramos; faríngeo, pretramticus e póstrematicus. O ramo faríngeo contém apenas fibras viscerossensoriais gerais para o epitélio faríngeo e especiais para o pseudobrânquio. Fibras viscerossensoriais gerais também são transportadas por ramos pretrematicus e posttrematicus para o revestimento epitelial da faringe. As fibras sensoriais especiais são transportadas pelo ramus pretrematicus para as papilas gustativas e pelo ramus posttrematicus para os filamentos branquiais. O ramo pretrematicus também carrega fibras visceromotoras para o primeiro adutor arcus branchialis e para o primeiro músculo oblíquo ventral.

Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus / Estudos anatômicos comparativos dos nervos cranianos de embriões totalmente formados da tilápia do Nilo Oreochromis niloticus (Ostiechthyes Cichlidae). I. Nervus glossopharyngeus

The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.(AU)

A organização das raízes, gânglios e a distribuição periférica dos nervos cranianos dos embriões totalmente formados de Oreochromis niloticus são examinados nas seções transversais seriais. Esses nervos carregam fibras, que também foram analisadas. Os resultados deste estudo demonstraram que o nervo glossofaríngeo se origina por meio de apenas uma raiz, que sai do crânio pelo forame glossofaríngeo. Este nervo fornece fibras (visceromotoras) para os primeiros músculos levantadores do arco branquial interno e externo. Existe um único gânglio epibranquial (petroso) localizado extracranialmente. Nervus glossopharyngeus tem três ramos; faríngeo, pretramticus e póstrematicus. O ramo faríngeo contém apenas fibras viscerossensoriais — gerais para o epitélio faríngeo e especiais para o pseudobrânquio. Fibras viscerossensoriais gerais também são transportadas por ramos pretrematicus e posttrematicus para o revestimento epitelial da faringe. As fibras sensoriais especiais são transportadas pelo ramus pretrematicus para as papilas gustativas e pelo ramus posttrematicus para os filamentos branquiais. O ramo pretrematicus também carrega fibras visceromotoras para o primeiro adutor arcus branchialis e para o primeiro músculo oblíquo ventral.(AU)

Molecular and morphological evidence of a new species of Crassicutis Manter 1936 (Digenea), a parasite of cichlids in South America.

A new species of Crassicutis Manter, 1936 (Digenea: Megaperidae) is described from the intestine of Satanoperca jurupari (Cichlidae) in the Amazon River basin, Brazil. The genus Crassicutis currently contains eight species. Crassicutis manteri n. sp. is morphologically very similar to Crassicutis cichlasomae Manter, 1936, a parasite of cichlids reported from Mexico, the Antilles, and Central and South America. Molecular data revealed that C. cichlasomae represents a species complex in Middle American cichlids. The new species can be readily distinguished from C. cichlasomae sensu lato, and the other congeners, by a combination of morphological traits such as a narrow, elongate mouth opening (versus spherical in other species), the tandem position of testes (symmetrical or oblique in most congeners), narrow body widening towards its posterior end (versus widely oval, leaf-like in other species), and short intestinal caeca ending close to the posterior end of the posterior testis (versus reaching more posteriorly in other species). Six novel sequences of 28S rDNA, ITS1, and cox1 were generated for two isolates of the new species. Sequences of the 28S rRNA gene were used to corroborate that Crassicutis is sister taxa of Homalometron Stafford, 1904. Mitochondrial DNA corroborated the distinction of the new species with previously sequenced congeners in Middle American cichlids; the interspecific divergence between the new species and the genetic lineages of C. cichlasomae was very high, varying between 23.7 and 27.2%. Biogeographical implications of our findings are briefly discussed including questionable validity of records of C. cichlasomae from South America.

Examination of ionoregulatory characteristics of South American cichlids.

We examined ionoregulatory traits of four cichlid species from South America, oscars (Astronotus ocellatus), Tapajos cichlids (Geophagus sp.), Macmaster's dwarf cichlids (Apistogramma macmasteri), and keyhole cichlids (Cleithracara maronii), all inhabitants of ion-poor waters. Km values for Na+ transport in fish held in 100 µmol L-1 Na+ water ranged from 49 to 143 µmol L-1, and Jmax values spanned 450 to 1205 nmol g-1 h-1. After one month in 1000 µmol L-1 Na+ water, kinetic parameters for Na+ uptake in three of the four species acclimated, but only oscars displayed the "typical" pattern of higher Km and lower Jmax values. Low pH water inhibited Na+ uptake (JinNa) in all, and stimulated Na+ efflux (JoutNa) 2.5 to 3.5-fold in three of the four species. Oscars alone had had a measurable JinNa at pH 3.5 and no stimulation of JoutNa. We measured JinNa in oscars and keyhole cichlids during exposure to 100 µmol L-1 Ethoxzolemide (EZ), an inhibitor of carbonic anhydrase, and 1 mmol L-1 NH4Cl (HEA). EZ inhibited JinNa by about 50% and HEA reduced JinNa by 80-90%. These results suggest that Na+ uptake involves H+ extrusion. Acute exposure to 1 µmol L-1 CuSO4 and 60 nmol L-1 AgNO3 inhibited JinNa in both species by 30-85%. Exposure of oscars to 5-fold higher concentrations of both metals did not further inhibit JinNa, but it did stimulate JoutNa 50-150%. The response to metals of both species are similar to other species that have been examined.

Equilibrium reproductive strategy of the peacock bass Cichla kelberi facilitates invasion into a Neotropical reservoir.

The reproductive strategy of the non-native predator cichlid Cichla kelberi was determined to explain its success after more than 60 years of being introduced into an isolated reservoir in southeastern Brazil. This was one of the first-known translocations of the genus Cichla out of its natural range. Macro- and microscopy characteristics of the gonadal development stages and the maturation phases, along with the reproductive features (size at first maturation size, gonado-somatic index and sex ratio), were described. It was hypothesized that the stable conditions of the reservoir, with low connectivity, weakly defined spatial gradient and slight seasonal changes in environmental variables, favour the equilibrium strategy that enables predators to have high offspring survivorship because of great parental investment in individual progeny. Sex ratio was well balanced, with males and females reaching first maturity between 30.0 and 28.6 cm total length (LT ), respectively. The stages of oocyte (primary and secondary growth, vitellogenic and atresia) and spermatocyte (spermatogonia, spermatocytes, spermatids and spermatozoa) development were identified. Five phases of gonadal development (immature, developing, spawning capable, regressing and regenerating) were described for both sexes. A long reproductive season was found, with spawning peaks in August/September and, to a lesser extent, in April/May. Parental care and spawns in parcels (batch spawns) corroborated the raised equilibrium strategy that was effective in this isolated reservoir. This species developed reproductive mechanisms that fit to different environmental conditions, with multiple spawning being associated with lentic environments and asynchronous development of oocytes, which are released over long periods. The reproductive plasticity in reservoirs may be one of the main factors inherent to the successful of colonization and establishment of the peacock bass in the environments in which they were introduced.

Encephalon gross morphology of the cichlid Geophagus sveni (Cichlidae: Geophagini): Comparative description and ecological perspectives.

The encephalon gross morphology of Geophagus sveni is described, compared between male and female specimens and discussed in relation to evolutionary, ecological and behavioural aspects. The Student's t-test revealed that there are no sexual dimorphism regarding the volume or linear measurements obtained from the main encephalon subdivisions (telencephalon, tectum mesencephali, cerebellum, gustative lobes, hypothalamus and hypophysis) in proportion to encephalon length, which is congruent with the absence of external dimorphic characters and presence of biparental care behaviour. In all specimens examined, the tectum mesencephali is the largest structure of the encephalon, which may be explained by feeding habit and by the importance of the vision center in a social context (i.e., brood guarding and territory defence, which are common behaviours in cichlids). Also, the lobus vagi is more developed than usual for other teleosts, which may be explained by the presence, in G. sveni as well as in other Geophagini species, of a differentiated pharyngeal apparatus, probably an adaptation to winnowing, a specialized feeding habit. The little intraspecific variation in neuroanatomical characters observed herein indicates a possible source of morphological characters to be explored in cichlid phylogeny.

Biologia alimentar de Aequidens tetramerus em macrófitas aquáticas de lagos de várzea da reserva de desenvolvimento sustentável Mamirauá, Região do Médio Solimões, Estado do Amazonas, Brasil / Food biology of Aequidens tetramerus in floodplain lake macrophytes in the Mamirauá sustainable development reserve, Mid-Solimões Region, State of Amazonas, Brazil / Biología alimentaria del Aequidens tetramerus en macrófitas acuáticas de lagos de várzea de la reserva de desarrollo sostenible Mamirauá, Región del Medio Solimões, Estado de Amazonas, Brasil

Estudos sobre a alimentação de peixes são fundamentais para compreender as relações tróficas e estrutura de comunidades ícticas. A espécie em estudo Aequidens tetramerus pertence à família Cichlidae que detém mais de 450 espécies para os neotrópicos, sendo que destes, 287 habitam a América do Sul. Objetivou-se com este estudo compreender a dieta e padrão alimentar de A. tetramerus em lagos de várzea nos ambientes de macrófitas aquáticas da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), Estado do Amazonas. A análise da dieta foi feita a partir da averiguação do conteúdo estomacal de 59 indivíduos. Determinou-se o Grau de Repleção Estomacal (GRE), Frequência de Ocorrência (FO%), Frequência de Biomassa (FB%) e o Índice de Importância Alimentar (IAi %). Segundo o (GRE), 28 espécimes (39,4%) apresentaram estômagos vazios. A dieta de A. tetramerus foi composta por 12 itens alimentares diferentes. Entretanto, poucos foram predominantes com destaque para insetos (12,6% e 42,7%), em FO% e FB%, respectivamente. Pode-se inferir que A. tetramerus possui hábito carnívoro com tendência a insetivoria, pois quando realizado a combinação dos métodos, por meio da determinação do (IAi %) para verificar a importância das 12 categorias que compuseram a dieta, o item inseto também obteve o maior valor (IAi = 0,71%). Este fato pode estar relacionado ao próprio ambiente de macrófitas aquáticas, pois este é um habitat ideal para a reprodução e desenvolvimento de insetos.

Studies on the feeding habits of fish are key to understanding the trophic relationships and the structure of ictic communities. The species under study, Aequidens tetramerus, belongs to the Cichlidae family which has over 450 species for the neotropics, of which 287 inhabit South America. The aim of this study was to understand the diet and dietary patterns of A. tetramerus in floodplain lakes in the aquatic macrophyte environments of the Mamirauá Sustainable Development Reserve (RDSM) in the state of Amazonas. The diet was analyzed by investigating the stomach contents of 59 individuals. The degree of stomach repletion (DRS), frequency of occurrence (FO%), frequency of biomass (FB%), and dietary importance index (IAi%) were determined. According to DSR, 28 specimens (39.4%) had empty stomachs. The diet of A. tetramerus was composed of 12 different food items. However, only a few were predominant, with emphasis to insects (12.6% and 42.7% in FO% and FB%, respectively). It can be inferred that A. tetramerus has carnivorous habits with a tendency to be an insectivore, since when the combination of methods was performed, by determining the IAi% to verify the importance of the 12 categories that composed the diet, the insect category also presented the highest value (IAi = 0.71%). This fact may be related to the aquatic macrophyte environment itself, as this is an ideal habitat for the reproduction and development of insects.

Estudios sobre la alimentación de peces son fundamentales para comprender las relaciones tróficas y estructura de comunidades ícticas. La especie en estudio, Aequidens tetramerus, pertenece a la familia Cichlidae que posee más de 450 especies en neo trópicos, 287 de los cuales habitan en América del Sur. El objetivo de este estudio yace en la compresión de la dieta y el patrón alimentar del A. tetramerus en lagos de vega en los ambientes de macrófitas acuáticas de la Reserva de Desarrollo Sostenible de Mamirauá (RDSM), en el Estado de Amazonas. El análisis de la dieta se realizó investigando el contenido estomacal de 59 individuos. Se determinaron el Grado de Repleción Estomacal (GRE), Frecuencia de Ocurrencia (FO%), Frecuencia de Biomasa (FB%) y el Índice de Importancia Alimentar (IAi%). Según GRE, 28 muestras (39,4%) tenían estómagos vacíos. La dieta de A. tetramerus consistió en 12 alimentos diferentes. Sin embargo, pocos fueron predominantes, con énfasis en insectos (12.6% y 42.7%), en FO% y FB%, respectivamente. Se puede inferir que el A. tetramerus tiene un hábito carnívoro con tendencia insectívora, porque cuando se realiza la combinación de los métodos, determinando el (IAi%) para verificar la importancia de las 12 categorías que componían la dieta, el ítem insecto también obtuvo el valor más alto (IAi = 0.71%). Este hecho puede estar relacionado con el propio ambiente de macrófitas acuáticas, ya que este es un hábitat ideal para la reproducción y el desarrollo de insectos.

Biologia alimentar de Aequidens tetramerus em macrófitas aquáticas de lagos de várzea da reserva de desenvolvimento sustentável Mamirauá, Região do Médio Solimões, Estado do Amazonas, Brasil / Food biology of Aequidens tetramerus in floodplain lake macrophytes in the Mamirauá sustainable development reserve, Mid-Solimões Region, State of Amazonas, Brazil / Biología alimentaria del Aequidens tetramerus en macrófitas acuáticas de lagos de várzea de la reserva de desarrollo sostenible Mamirauá, Región del Medio Solimões, Estado de Amazonas, Brasil

Estudos sobre a alimentação de peixes são fundamentais para compreender as relações tróficas e estrutura de comunidades ícticas. A espécie em estudo Aequidens tetramerus pertence à família Cichlidae que detém mais de 450 espécies para os neotrópicos, sendo que destes, 287 habitam a América do Sul. Objetivou-se com este estudo compreender a dieta e padrão alimentar de A. tetramerus em lagos de várzea nos ambientes de macrófitas aquáticas da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), Estado do Amazonas. A análise da dieta foi feita a partir da averiguação do conteúdo estomacal de 59 indivíduos. Determinou-se o Grau de Repleção Estomacal (GRE), Frequência de Ocorrência (FO%), Frequência de Biomassa (FB%) e o Índice de Importância Alimentar (IAi %). Segundo o (GRE), 28 espécimes (39,4%) apresentaram estômagos vazios. A dieta de A. tetramerus foi composta por 12 itens alimentares diferentes. Entretanto, poucos foram predominantes com destaque para insetos (12,6% e 42,7%), em FO% e FB%, respectivamente. Pode-se inferir que A. tetramerus possui hábito carnívoro com tendência a insetivoria, pois quando realizado a combinação dos métodos, por meio da determinação do (IAi %) para verificar a importância das 12 categorias que compuseram a dieta, o item inseto também obteve o maior valor (IAi = 0,71%). Este fato pode estar relacionado ao próprio ambiente de macrófitas aquáticas, pois este é um habitat ideal para a reprodução e desenvolvimento de insetos.(AU)

Studies on the feeding habits of fish are key to understanding the trophic relationships and the structure of ictic communities. The species under study, Aequidens tetramerus, belongs to the Cichlidae family which has over 450 species for the neotropics, of which 287 inhabit South America. The aim of this study was to understand the diet and dietary patterns of A. tetramerus in floodplain lakes in the aquatic macrophyte environments of the Mamirauá Sustainable Development Reserve (RDSM) in the state of Amazonas. The diet was analyzed by investigating the stomach contents of 59 individuals. The degree of stomach repletion (DRS), frequency of occurrence (FO%), frequency of biomass (FB%), and dietary importance index (IAi%) were determined. According to DSR, 28 specimens (39.4%) had empty stomachs. The diet of A. tetramerus was composed of 12 different food items. However, only a few were predominant, with emphasis to insects (12.6% and 42.7% in FO% and FB%, respectively). It can be inferred that A. tetramerus has carnivorous habits with a tendency to be an insectivore, since when the combination of methods was performed, by determining the IAi% to verify the importance of the 12 categories that composed the diet, the insect category also presented the highest value (IAi = 0.71%). This fact may be related to the aquatic macrophyte environment itself, as this is an ideal habitat for the reproduction and development of insects.(AU)

Estudios sobre la alimentación de peces son fundamentales para comprender las relaciones tróficas y estructura de comunidades ícticas. La especie en estudio, Aequidens tetramerus, pertenece a la familia Cichlidae que posee más de 450 especies en neo trópicos, 287 de los cuales habitan en América del Sur. El objetivo de este estudio yace en la compresión de la dieta y el patrón alimentar del A. tetramerus en lagos de vega en los ambientes de macrófitas acuáticas de la Reserva de Desarrollo Sostenible de Mamirauá (RDSM), en el Estado de Amazonas. El análisis de la dieta se realizó investigando el contenido estomacal de 59 individuos. Se determinaron el Grado de Repleción Estomacal (GRE), Frecuencia de Ocurrencia (FO%), Frecuencia de Biomasa (FB%) y el Índice de Importancia Alimentar (IAi%). Según GRE, 28 muestras (39,4%) tenían estómagos vacíos. La dieta de A. tetramerus consistió en 12 alimentos diferentes. Sin embargo, pocos fueron predominantes, con énfasis en insectos (12.6% y 42.7%), en FO% y FB%, respectivamente. Se puede inferir que el A. tetramerus tiene un hábito carnívoro con tendencia insectívora, porque cuando se realiza la combinación de los métodos, determinando el (IAi%) para verificar la importancia de las 12 categorías que componían la dieta, el ítem insecto también obtuvo el valor más alto (IAi = 0.71%). Este hecho puede estar relacionado con el propio ambiente de macrófitas acuáticas, ya que este es un hábitat ideal para la reproducción y el desarrollo de insectos.(AU)

Biologia alimentar de Aequidens tetramerus em macrófitas aquáticas de lagos de várzea da reserva de desenvolvimento sustentável Mamirauá, Região do Médio Solimões, Estado do Amazonas, Brasil / Food biology of Aequidens tetramerus in floodplain lake macrophytes in the Mamirauá sustainable development reserve, Mid-Solimões Region, State of Amazonas, Brazil / Biología alimentaria del Aequidens tetramerus en macrófitas acuáticas de lagos de várzea de la reserva de desarrollo sostenible Mamirauá, Región del Medio Solimões, Estado de Amazonas, Brasil

Estudos sobre a alimentação de peixes são fundamentais para compreender as relações tróficas e estrutura de comunidades ícticas. A espécie em estudo Aequidens tetramerus pertence à família Cichlidae que detém mais de 450 espécies para os neotrópicos, sendo que destes, 287 habitam a América do Sul. Objetivou-se com este estudo compreender a dieta e padrão alimentar de A. tetramerus em lagos de várzea nos ambientes de macrófitas aquáticas da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), Estado do Amazonas. A análise da dieta foi feita a partir da averiguação do conteúdo estomacal de 59 indivíduos. Determinou-se o Grau de Repleção Estomacal (GRE), Frequência de Ocorrência (FO%), Frequência de Biomassa (FB%) e o Índice de Importância Alimentar (IAi %). Segundo o (GRE), 28 espécimes (39,4%) apresentaram estômagos vazios. A dieta de A. tetramerus foi composta por 12 itens alimentares diferentes. Entretanto, poucos foram predominantes com destaque para insetos (12,6% e 42,7%), em FO% e FB%, respectivamente. Pode-se inferir que A. tetramerus possui hábito carnívoro com tendência a insetivoria, pois quando realizado a combinação dos métodos, por meio da determinação do (IAi %) para verificar a importância das 12 categorias que compuseram a dieta, o item inseto também obteve o maior valor (IAi = 0,71%). Este fato pode estar relacionado ao próprio ambiente de macrófitas aquáticas, pois este é um habitat ideal para a reprodução e desenvolvimento de insetos.(AU)

Studies on the feeding habits of fish are key to understanding the trophic relationships and the structure of ictic communities. The species under study, Aequidens tetramerus, belongs to the Cichlidae family which has over 450 species for the neotropics, of which 287 inhabit South America. The aim of this study was to understand the diet and dietary patterns of A. tetramerus in floodplain lakes in the aquatic macrophyte environments of the Mamirauá Sustainable Development Reserve (RDSM) in the state of Amazonas. The diet was analyzed by investigating the stomach contents of 59 individuals. The degree of stomach repletion (DRS), frequency of occurrence (FO%), frequency of biomass (FB%), and dietary importance index (IAi%) were determined. According to DSR, 28 specimens (39.4%) had empty stomachs. The diet of A. tetramerus was composed of 12 different food items. However, only a few were predominant, with emphasis to insects (12.6% and 42.7% in FO% and FB%, respectively). It can be inferred that A. tetramerus has carnivorous habits with a tendency to be an insectivore, since when the combination of methods was performed, by determining the IAi% to verify the importance of the 12 categories that composed the diet, the insect category also presented the highest value (IAi = 0.71%). This fact may be related to the aquatic macrophyte environment itself, as this is an ideal habitat for the reproduction and development of insects.(AU)

Estudios sobre la alimentación de peces son fundamentales para comprender las relaciones tróficas y estructura de comunidades ícticas. La especie en estudio, Aequidens tetramerus, pertenece a la familia Cichlidae que posee más de 450 especies en neo trópicos, 287 de los cuales habitan en América del Sur. El objetivo de este estudio yace en la compresión de la dieta y el patrón alimentar del A. tetramerus en lagos de vega en los ambientes de macrófitas acuáticas de la Reserva de Desarrollo Sostenible de Mamirauá (RDSM), en el Estado de Amazonas. El análisis de la dieta se realizó investigando el contenido estomacal de 59 individuos. Se determinaron el Grado de Repleción Estomacal (GRE), Frecuencia de Ocurrencia (FO%), Frecuencia de Biomasa (FB%) y el Índice de Importancia Alimentar (IAi%). Según GRE, 28 muestras (39,4%) tenían estómagos vacíos. La dieta de A. tetramerus consistió en 12 alimentos diferentes. Sin embargo, pocos fueron predominantes, con énfasis en insectos (12.6% y 42.7%), en FO% y FB%, respectivamente. Se puede inferir que el A. tetramerus tiene un hábito carnívoro con tendencia insectívora, porque cuando se realiza la combinación de los métodos, determinando el (IAi%) para verificar la importancia de las 12 categorías que componían la dieta, el ítem insecto también obtuvo el valor más alto (IAi = 0.71%). Este hecho puede estar relacionado con el propio ambiente de macrófitas acuáticas, ya que este es un hábitat ideal para la reproducción y el desarrollo de insectos.(AU)

Neotropical Monogenoidea 62. Biotodomella mirospinata gen. nov., sp. nov. (Polyonchoinea: Dactylogyridae): a parasite of the gills of Biotodoma cupido (Cichliformes: Cichlidae), from the Peruvian Amazon

Biotodomella gen. nov. (Monogenoidea: Dactylogyridae) is proposed to accommodate Biotodomella mirospinata sp. nov., found on the gills of Biotodoma cupido (Heckel, 1840) (“cara bonita” or “green-streaked eartheater”), a freshwater cichlid from the Peruvian Amazon. The new genus and species differ from other Neotropical dactylogyrids in having the hooks of each hook pair well-differentiated from the remaining pairs, shafts varying in robustness, weakly sclerotized expansions at the proximal end of shaft, and a dorsal anchor with grooved shaft, bifid point. This study represents the first record of a monogenoid from a species of Biotodoma Eigenmann & Kennedy, 1903.(AU)

First molecular assessment of the interrelationships of cladorchiid digeneans (Digenea: Paramphistomoidea), parasites of Neotropical fishes, including descriptions of three new species and new host and geographical records.

The first molecular assessment of phylogenetic relationships of cladorchiid digeneans (superfamily Paramphistomoidea Fischoeder, 1901) from freshwater fishes based on 28S rDNA, ITS2 and cox1 sequences reveals the subfamilies Dadayiinae Fukui, 1929 and Kalitrematinae Travassos, 1933 as non-monophyletic, whereas Dadaytrema Travassos, 1931 represented by three species is monophyletic. Fourteen species of cladorchiids were found in characiform, perciform and siluriform fishes in the Neotropical Region (Brazil and Peru), with numerous new host and geographical records. The first scanning electron micrographs of seven species are presented. Two new species of dadayiine and one new species of kalitrematine paramphistomes are described. Microrchis macrovarium sp. n. from Pimelodella cristata (Müller et Troschel) (type host), Tetranematichthys quadrifilis (Kner) and Pterodoras granulosus (Valenciennes) in Brazil and Peru differs from all three congeners in that the testes are directly tandem, not oblique, and that the ovary, between the caecal ends, is widely separated from the testes. Pronamphistoma philippei sp. n. from Heros sp. in Brazil is distinguished from the type and only species, Pronamphistoma cichlasomae Thatcher, 1992, by the absence of the anterior collar-like expansion present in the type species, the presence of extramural rather than intramural pharyngeal sacs, and the unusual development of the dorsal and ventral exterior circular muscle fibre series in the acetabulum. Pseudocladorchis romani sp. n. from P. granulosus (type host), Brachyplatystoma vaillantii (Valenciennes), Calophysus macropterus (Lichtenstein), Megalodoras uranoscopus (Eigenmann et Eigenmann) and Oxydoras niger (Valenciennes) in Brazil and Peru, is most similar to Pseudocladorchis nephrodorchis Daday, 1907 but differs in the shape of the testes (irregular, versus reniform in the latter species) and the size of the ovary (as large as, or larger than, the testes in the new species). The generic diagnosis of Pronamphistoma Thatcher, 1992 is amended. Dadaytremoides parauchenipteri Lunaschi, 1989 is transferred to Doradamphistoma Thatcher, 1979 as D. parauchenipteri (Lunaschi, 1989) comb. n. based on morphological and molecular evidence.

Neotropical Monogenoidea 62. Biotodomella mirospinata gen. nov., sp. nov. (Polyonchoinea: Dactylogyridae): a parasite of the gills of Biotodoma cupido (Cichliformes: Cichlidae), from the Peruvian Amazon

Biotodomella gen. nov. (Monogenoidea: Dactylogyridae) is proposed to accommodate Biotodomella mirospinata sp. nov., found on the gills of Biotodoma cupido (Heckel, 1840) (“cara bonita” or “green-streaked eartheater”), a freshwater cichlid from the Peruvian Amazon. The new genus and species differ from other Neotropical dactylogyrids in having the hooks of each hook pair well-differentiated from the remaining pairs, shafts varying in robustness, weakly sclerotized expansions at the proximal end of shaft, and a dorsal anchor with grooved shaft, bifid point. This study represents the first record of a monogenoid from a species of Biotodoma Eigenmann & Kennedy, 1903.

Morphological and molecular characterisation of a new species of Gyrodactylus von Nordmann, 1832 (Monogenoidea: Gyrodactylidae) of cichlid fishes (Perciformes) from Mexico.

Gyrodactylus mojarrae n. sp. is described from the gills of the Neotropical cichlids Thorichthys maculipinnis, Rocio octofasciata, Vieja zonata and V. fenestrata from several localities across southern Mexico. The new species is erected on the basis of the morphology of the haptoral elements (anchors, bars and hooks), and its phylogenetic position within the Gyrodactylidae is evaluated based on the analysis of partial sequences of the ITS1, 5.8 rRNA gene and ITS2. Gyrodactylus mojarrae n. sp. differs from other congeneric species by having hooks with a straight shaft and recurved point, pointed toe and convex heel, presence of reduced superficial anchor roots, by the number and disposition of spinelets of the male copulatory organ, and the absence of shield and lateral processes of the superficial bar. Molecular circumscription of isolates of G. mojarrae n. sp. from different host and hydrological basins showed that these isolates are conspecific and represent a distinct lineage from other congeners, including newly sequenced isolates of Gyodactylus sp. A and Gyrodactylus sp. B from Astyanax mexicanus (Characidae) and Gobiomorus dormitor (Eleotridae), respectively. Genetic affinities of Gyodactylus sp. A and B indicate that they might represent undescribed species infecting freshwater fish from the Americas.